Substantially neutral magnesium salt of a phosphoric acid ester of oxethylated nonylphenol



United States Patent SUESTANHALLY NEUTRAL MAGNESIUM SALT QB A PHQSEHSRICA61!) ETER 0F (BXETHYL- ATED NQNYL PHENOL Edwin E. Michaela, Stamford,(Jenn, assign-er to Stamford Chemical Industries, Inc, Stamford, Conn, acorporation of Delaware No Drawing. (Briginal appiicatiou May 19, 196i),filer. No. 28,@21. Divided and this application Nov. 6, 1%1, Ser. No.150,146

1 Claim. (til. 260-461) The present invention relates to novel magnesiumsalts of monoand (ii-phosphate esters of oxyethylated higher alkylphenols or of oxyethylated higher aliphatic monohydric alcohols andmethods for their preparation. More particularly, it relates to suchnovel magnesium salts of monoand di-phosphate esters of enhanceddetergency in an organic drycleaning solvent and compositions containingthe same.

It is considered good practice in the drycleaning inclustry to add smallamounts of a detergent to an organic solvent to effect eflicient removalof sweet stains and soil and to reduce graying of a soiled garment orfabric. Unfortunately, widely used detergents such as the cationics,anionics and non-ionics are not wholly satisfactory, since many exhibitrelatively low levels of both sweet stain and soil removal as well asthe avoidance of graying or soil redeposition. A pressing need for adetergent which provides for high levels of stain and soil removal aswell as whiteness retention exists. A detergent which possesses theseproperties if one could be found, would be highly desirable.

It is, therefore, a principal object of the present invention to providenovel detergent compounds capable of being dissolved in organicsolvents. It is a further object to provide novel organic solventsoluble phosphoric acid ester detergents which are capable of enhancingsoil and sweet stain removal while increasing whiteness re tention indrycleaning operations. Other objects and advantages will become clearfrom a reading of the ensuing description.

To this end, a magnesium salt of either oxyethylated higher alkyl phenolphosphoric acid esters or oxyethylated higher aliphatic alcoholphosphoric acid esters has been provided which, when incorporated in adrycleaning solvent, markedly aifects the drycleaning operation. Theclass of detergents as included within the purview of the presentinvention are: the magnesium salts of oxyethylated higher alkyl phenolphosphoric acid monoand diesters as well as the oxyethylated higheraliphatic alcohol monoand di-phosphoric acid esters.

It has been found that, according to the process of the invention, themagnesium salts of the phosphoric acid monoand di-esters of oxyethylatedhigher alkyl phenols or aliphatic monohydric alcohols can be preparedand incorporated in a drycleaning solvent. For example, either the oxideor hydroxide of magnesium is reacted with phosphoric acid esters ofeither oxyethylated alkylphenols or oxyethylated higher aliphaticalcohols. Such esters are prepared initially by reacting eitheroxyethylated phenols or oxyethylated higher aliphatic alcohols withphosphorous pentoxide to obtain a mixture of monoand di-phosphoric acidesters.

The preparation of the phosphoric acid esters contemplated by thepresent invention is accomplished in a straight-forward manner. Ingeneral, about one mol of either a higher alkyl phenol or a higheraliphatic monohydric alcohol is reacted with from about one to aboutfifteen mols of ethylene oxide. It is a good practice, however, to reactof from about 3.5 to about 8.5 mols of ethylene oxide per 'mol of higheralkyl phenol or higher aliphatic alcohol. Mixtures of such oxyethylated"Ice phenols or alcohols are also contemplated. Thus, for example, asubstantially mono-oxyethylated phenol, prepared by reacting nonylphenol with one mol of ethylene oxide, can be admixed in equalproportions with a polyoxyethylated phenol, such as nonyl phenol reactedwith about twelve mols of ethylene oxide. Such mixtures have been foundto possess exceptional emulsifying as well as detergent properties whenincorporated in a drycleaning solvent.

Among the higher alky'l phenols or higher aliphatic monohydric alcoholsincluded are for example: p-octyl phenol, p-nonyl phenol, p,odinonylphenol, tridecyl phenol, octyl alcohol, 'decyl alcohol, lauryl alcoholand tridecyl alcohol. Since the octyland nonyl-phenols are readilycommercially available, they constitute a preferred embodiment.

Resultant oxyethylated higher alkyl phenols or oxyethylated higheraliphatic monohyclric alcohols are next reacted with phosphorouspentoxide at temperatures between about 70 C. and about 140 C., andpreferably from C. to C., for from about 5 to 250 hours or more, in anysuitable closed reaction vessel. Usually, molar quantities of from abouttwo and one-half to five mols, and preferably from 3.5 to 4.5 mols, ofthe phenol or alcohol reactant per mol of phosphorous pentoxide aresufiicient to effect the desired reaction.

The aforementioned reaction results in a mixture of monoanddi-phosphoric acid esters. Esters of complex phosphoric acids which mayalso be formed can be hydrolyzed to the phosphate esters and to insurethat a mol ratio of di-esters to mono-esters in said ester mixture bepresent in the range of from 1 to 1 or greater, respectively. Though themono ester can be separated from the di ester, it has been found that amixture of diand mono-ester is highly useful as the detergent inadmixture with the dry-cleaning solvent. It has been further found thatthe mol ratio range of di-ester to mono-ester will widely vary fromabout 120.5 to 1:20 or greater, and preferably from 1:1 to 1:6respectively, as determined by electrometric titration at a glasselectrode. In general, a phosphate ester is titrated in an aqueousmedium with standard alkali. Two endpoints are obtained. The firstendpoint, termed (H reflects the hydrogen ion of the di-ester and thefirst hydrogen ion of the monoester. The second endpoint, termed (Hreflects the second hydrogen ion of the mono-ester.

The ratio can be expressed as follows:

Mo1s of (ii-ester ba Mols of rnono-ester 2ab in which Variations in themol ratio of dito mono-esters prior to reaction with a magnesium baseis, for instance, dependent upon the phosphorous pentoxide to phenol oralcohol mol reaction ratio. Additionally, time and temperature arefactors which may affect the mol ester ratio. Thus, for instance, wherethe mol ratio of the alcohol or phenol reactant to phosphorous pentoxideis low, say in the mol ratio of 3:1, respectively, or where the molratio is about 4: 1, but the time employed during the reaction isexcessively long, say 14 days or more, or where temperatures areexcessively high, say in excess C., polymeric complex phosphoric acidesters, such as esters of pyrophosphoric acid, are formed. Under thelatter reaction conditions the mol ratio of di-ester to monoester ofresultant phosphate ester is less than 1:1, and about 120.5. Whenmagnesium salts of such polymeric complex phosphoric acid ester areprepared, the detergency values with respect to whiteness retention andsoil removal markedly decrease.

Notwithstanding polymeric complex phosphoric acid ester formation, suchcomplex can be converted unexpectedly to useful phosphate esters ofenhanced detergency by hydrolyzing the polymeric complex prior tomagnesium salt formation. The hydrolysis is accomplished by adding from5% to or more water based on the weight of the polymeric complex, andheating the mixture to from about 85 C. to 120 C. for from about one toabout twenty-four hours. When hydrolysis is effected, and for goodpractice should be effected if the acid number of a sample of hydrolyzedester increases 1% or more, pH titration measurements are taken todetermine the mol ratio of resultant esters. It is found that the molratio of di-ester to mono-ester is increased from less than 1:1 to l to12, respectively. However, when both the phenol-ethylene oxidecondensate is highly hydrophobic and the condensate to phosphorouspentoxide mol ratio is high, say in the ratio of 2.7 to 1, resultantdiester to mono-ester ratio found is 1-20 or higher, respectively.

In accordance with the practice of the invention, a magnesium base, suchas magnesium oxide or magnesium hydroxide, and the aforementionedphosphoric acid ester are admixed in an aqueous medium and preferably inan aqueous alcoholic medium. The latter mixture is agitated for fromabout one-half hour to two hours. The pH of the reaction mixture isintermittently tested. For instance, when a pH of 6.5 to about 8 isobtained, the reaction is then deemed to be completed and the reactionsolvent removed to recover resultant magnesium salt. The latter is nextoven dried at about 88 C.99 C. It can then be incorporated into adrycleaning solvent.

Any commercially available dry'cleaning solvent is with in the purviewof the instant invention. Illustrative solvents are: Stoddard solvent,perchlorethylene, trichloroethylene and carbon tetrachloride. A goodpractice is to add the magnesium salts described above to any one of thedrycleaning solvents in amounts ranging from about 0.2% to about 4% ofsaid salt based upon the weight of the solvent.

Advantageously, drycleaning solvents containing the magnesium salts ofthe present invention are capable of emciently cleaning garments,textiles, fabrics and the like so as to leave them substantially freefrom sweet stains and soil as well as demonstrating a marked decreasetoward greying of such materials. Garments thus cleaned have anexcellent hand and are free from harshness generally found in the usualdrycleaning practice. Further, such garments when subjected to tumblingto dry the same after cleaning do not produce lintlng. Unexpectedly,even where the relative humidity is low, static electricity usuallyexperienced while tumbling garments is not built up. It is postulated,without being limited thereto, that this beneficial effect may be due tothe adsorption of the magnesium salts in minute quantity during thecleaning process.

In order to facilitate an understanding of the invention, the followingexamples are given as merely illustrative of the best practices and notas limitative thereof. The parts given are by weight unless otherwisestated.

EXAMPLE 1 Into a suitable pressure vessel is added one mol ofphosphorous pentoxide and four mols of polyoxyethylated nonylphenolcontaining an average of 5.5 oxyethyl groups. The vessel is next sealedand heated to about 99 C. for 168 hours. Heating is discontinued, thereaction vessel opened and the contents therein are slowly cooled toroom temperature and removed from the reaction vessel.

A small amount of the reaction product is analyzed to determine the typeof ester present. It is found that the acid number of reaction productis 81.8 and consists of diand mono-esters in a mol ratio of 1 to 1.5respectively.

1000 parts of the esters so prepared (one mol) and 30 parts of magnesiumoxide (0.75 mol) are stirred in a. suitable vessel containing 40 partsof water, parts methyl amyl alcohol for about one hour. The pH of theresultant paste, when diluted with water for testing, is 7.0. A clearopalescent paste, dispersible in Water and soluble in perchlorethyleneand Stoddard solvent is obtained.

EXAMPLE 2 Example 1 is repeated in every material respect, except thatpolyoxyethylated octyl phenol containing an average of 4.5 oxyethylatedgroups is substituted for the polyoxyethylated nonyl phenol reactant. Ontitration, the mol ratio of di-ester to mono-ester in the estercomposition is 1 to 1.1 and the acid number is 100.8.

The magnesium salt of phosphoric acid ester is prepared as in thepreceding example. Resultant salt is characterized as being relativelyinsoluble in water and more efficient in emulsifying petroleum solventsthan the higher ethoxylated salt of Example 1, above.

EXAMPLE 3 Example 1 is repeated in every material respect except thatpolyoxyethylated tridecyl phenol containing an average of 7.5 oxyethylgroups is substituted for the aforementioned poly'oxyethylatednonylphenol reactant. On titration the mol ratio of di-ester tomono-ester is 1:1.2. The acid number of the latter composition is 75.0.

The magnesium salt of phosphoric acid ester is prepared as in theforegoing Example 1 except magnesium hydroxide is substituted for themagnesium oxide of said example. The salt is characterized as: a pastesoluble in kerosene, in kerosene type fuels and motor lube oils. Itshows excellent dispersing power for carbon in these media. 7

EXAMPLE 4 Repeating Example 1 in every detail except thatpolyoxyethylated nonyl phenol containing an average of 12.4 oxyethylgroups is substituted for the polyoxyethylated nonyl phenol reactant setforth therein. The mol ratio of dito mono-ester in the ester compositionis 1 to 1 and the acid number is 47.04.

The magnesium salt of phosphoric acid ester is next prepared as inExample 1 and the resultant salt is characterized as being soluble inperchloret-hylene and in Water, but not soluble in kerosene.

EXAMPLE 5 Example. 1 is repeated in every material detail except thatthe polyoxyethylated nonyl phenol containing an average of 1. 1 oxyethylgroups is substituted for the polyoxyethylated nonyl phenol reactant asset forth there in. The dito mono-ester mol ratio in the phosphate estercomposition is 1 to 1.3 and the acid number is 121.0. The magnesium saltis next prepared as in Example 1 and resultant salt is soluble inkerosene and insoluble in water. The magnesium salt is a hard waxysolid.

EXAMPLE 6 Equal parts of the magnesium salts of polyoxyethylated nonylphenol as prepared in Examples 4 and 5 are admixed and about 5% of themixture is incorporated in a perchlorethylene drycleaning solventcontaining 10% moisture.

The salt mixture demonstrates marked activity as an emulsifier in thelatter drycleaning solvent system. It is noted that separation of thewater phase and organic solvent phase does not take place.

EXAMPLE 7 To parts of tridecyl alcohol ethylene oxide condensate (0.146mol), prepared by reacting 1 mol of the alcohol with seven mols ofethylene oxide, is added, in

a suitable reaction vessel, 5.2 parts of phosphorous pentoxide (0.037mols) while stirring at a temperature of from about 50 C. to about 55C., until all the phosphorous pentoxide is dissolved therein. Thetemperature is next increased to about 96 C. and heated for a period of170 hours. On titration the dito mono-ester mol ratio of the estercomposition is 1 to 1.8 and the acid number is 96.3.

Resultant reaction product is cooled to room temperature and to theclear viscous liquid is added a mixture of 8 parts (by volume) of methylamyl alcohol and 4 parts of water.

To the aforementioned mixture is next added three and one-half parts oflightly precipitated magnesium oxide and the mixture vigorously stirred.A pH of 6.7 is noted in testing an aqueous dispersion. A clearopalescent paste, dispersible in water and soluble in Stoddard solventis obtained.

EXAMPLE 8 4.5 mols of polyoxyethylated nonyl phenol containing anaverage of 4.5 oxyethylated groups is added 1 mol of phosphorouspentoxide to a suitable reaction vessel which can be closed, heating theclosed reaction for fourteen days and at a temperature of about 99 C. Ontitration of the mixture, the dito monoester mol ratio of the estercomposition is l to 1.3. The composition is found to possess an acidnumber of 85.2.

The composition is next reacted with sufficient magnesium oxide to forma magnesium salt of pH7.

Though the mol ratio of dito monoester is l to 1.3, nonetheless thedrastic heating condition for the prolonged period results in aninferior product of poor detergency.

EXAMPLE 9 50 parts of ester product of claim 8, prior to magnesium oxideneutralization, is hydrolyzed with 5 parts of water in a closed reactionvessel at about 88 C. for 24 hours. The resultant ester compositionshows a mol ratio of di-ester to mono-ester as determined by titrationto be 1 to 1.5, respectively, having an acid number equal to 103.0.

The hydrolyzed ester product is next neutralized with magnesium oxide toa pH equal to 7. This product demonstrates better than averagedetergency.

EXAMPLE 10 To demonstrate that the above exempliied salts are valuabledetergent adjuvants in dry cleaning solvents, each of tne salts istested in the following manner:

In accordance with the procedure set forth in the Technical Manual ofthe American Association of Textile Chemists and Colorist at page 90,1959 edition, pint jars are charged with 100 ml. of perchlorethylenesolvent containing 0.7% of the compound to be tested. Twenty stainlesssteel balls are added to each jar with the test fabric swatches. Thesefabric swatches are both cotton and wool which have been previouslysoiled by printing or immersion in a greasy carbon soil. There isprovided in each jar both soiled and unsoiled swatch samples of cottonand Wool. The jars are then sealed and tumbled in an Atlas Launderometerfor twenty minutes. The swatches are removed, extracted and dried.

Reflectance values of the dried swatches as measured with a surfacerefiectomer are obtained. To determine the numerical values both of thepercent loss of brightness of the unsoiled swatches and the percentincrease in brightness of the soiled swatches, the reflectance values ofthe dried swatches to obtained are compared to the reflectance readings,prior to drycleaning of unsoiled and soiled swatches. The latterreadings are based on scale of 100 and 29, respectively. The results aretabularized below.

Table 1 Compound C W 0 (1 W d A-B *0 (Cotton redeposrtron 1ndex)= AWhere:

A= Original reflectance of unsoiled cotton, and B =Reflectance unsoiledcotton after cleaning.

*Ww (Wool redeposition index) E Where:

0 =Original reflectance unsoiled Wool, and D =Retlcctance unsoiled woolafter cleaning.

Cd (Cotton cleaning index) =F-E Where:

E=Reflectance of soiled cotton, and F=Reflectance of soiled cotton aftercleaning.

Wa (W001 cleaning index) =HG Where:

G=Reflsctance 0f soiled wool, and

H=Refiectance of soiled Wool after cleaning.

The above values illustrate the effect of each of the phosphate esterson whiteness retention and detergency values. It will be seen that thedegree of ethoxylation affects both detergency and graying. In general,the lower the degree of ethoxyiation as in Example 5, the poorer theover-all results. However, the upper limit of ethoxylation is limited bythe decreasing solubility in organic solvents. This is influenced by thelength of the alkyl chain and by the amount of P 0 reacting with thecondensate.

EXAMPLE 1 1 To illustrate the criticality of both pH and the use ofmagnesium salts of the organic phosphate esters prepared in accordancewith the practice of the invention, several salts of the phosphate esterof Example 1 are prepared by reacting the phosphate ester with (a)alkali metal hydroxides, (b) alkaline earth metal hydroxide as well as(c) magnesium oxide, employing varying quanties to obtain correspondingsalts of varying pH. The sodium, potassium, lithium, calcium andmagnesium salts of the ester of Example 1 are readily prepared. Thelatter are tested in an Atlas launderometer as outlined in Example 10above. The results are tabularized below.

Table 2 Reflectance Readings Salt of Phosphate Ester Compound pH ofExample 1 Decrease From Original Unsoiled Swatches Increase on CleaningSoiled Swatches Cotton (0 W) Wool (WW) Cotton (Cd) Sodium Potassium-Lithium No'rE.Thc meanings or Ow W OJ, and W are the same as in Example10 above.

It will be noted that the magnesium salt of the ester is most usefulwhen it has been neutralized to a pH value of from about 6.5 to about8.0. Even at pH:7, the salts 7 other than the magnesium salt are, ingeneral, poor detergents.

EXAMPLE 12 The effect of variations of the tool ratio of ethoxylatedphenol to phosphorous pentoxide is determined by vary- 0 ing the rn-olratio. Results are tabulated below.

Table 3 Reflectance Readings 10 1 Ester is prepared by reacting theindicated mol quantity of oxyethylatcd phenol with one moi ofphosphorous pentoxidc by the process of Example 2.

Norm-The meanings of Ow, WW, Ca, and We are the same as given in Example10 above.

It will be seen from the above tabulated data that the best detergencyis obtained within the range of mol ratios of from 4.5 (phenol) to 1 (P0 to about 3.0 (phenol) 55 to 1 (P 0 as employed in the preparation ofthe phosphate esters.

it is an advantage of the present invention that the novel phosphateesters may be combined with other oil soluble detergents. Thus, forexample, oil-soluble mahogany sulfonates can be admixed with varyingamounts of phosphate ester as above defined to obtain enhanceddetergency and whiteness retention in drycleaning operations.

While the oil-soluble novel compounds hereinabove defined have beenincorporated in drycleaning solvents, it is also contemplated that theymay also be incorporated in fuel oils, such as diesel oil, gasoline, aswell as in motor oils.

This application is a division of my copencling application, Serial No.28,021, filed May 10, 1960.

I claim:

The substantially neutral magnesium salt of a phosphoric acid ester oioxyethylated nonyl phenol containing about 5.5 oxyetbyl groupsReferences Cited in the file of this patent UNITED STATES PATENTS2,177,983 Harris Oct. 31, 1939 2,353,471 Beadell Sept. 23, 19583,004,056 Nunn et a1. Oct. 10, 1961 3,004,057 Nunn Oct. 10, 19613,019,903 Clarke et al, Nov. 28, 1961

